The present invention relates to a testing apparatus, and more particularly to an arrangement for monitoring the eye movement of a viewer exposed to a given visual stimulus, such as an advertisement.
Advertising is regarded now and in all probability will continue to be so regarded as an important and highly useful service to generate and stimulate public interest in the advertised product. The spread of mass communications media in this country and abroad in the forms of newspapers, magazines, radio and television provide a convenient, effective avenue, for a price, to reach large numbers of people. Huge sums of money are expended on advertisements both on a national and local level and these, in turn, may have an impact on even significantly greater sums. The costs involved in the establishment of an advertisement campaign are willingly shouldered in the hope that it will have a favorable effect on profits. Much time, effort and thought are put into devising the various facets of advertising to maximize the benefits derived from the investment. One such facet concerns directing the campaign at the segment of the public believed to be the most likely targets for the advertised product. Thus, for example, if the product is more likely to be bought by a particular age group or profession or sex, the advertising medium catering to these people is chosen. Similarly, the content, form and presentation of the advertisement form another facet of advertising which receives considerable care and attention since, in the final analysis, it is the decisive factor in whether the product appears attractive enough to be distinctly remembered by the consumer while shopping. However, no matter how much effort, experience, and expertise are involved in the preparation of an advertisement, there is always the risk that it will miss its mark and fail to achieve its goal partially or even completely. This is due to the fact that the anticipated effectiveness of the advertisement is based on the opinions of those whose prepare it and these may not always coincide with its actual effect on the "typical" or "average" consumer. Since the expenditures on advertisements are so high, it is clearly highly desirable to minimize these risks. Some efforts to this end have taken the form of obtaining feedback from the public by way of preliminary selected samplings of viewer opinions for analysis and appropriate action before the full advertisement campaign is authorized. This permits the advertiser to ascertain whether the various facets of the advertising campaign are producing satisfactory results so that any existing problems can be eliminated and corrected at relatively low cost.
This aspect of advertising involving preliminary investigation is characterized by ever increasing sophistication. Its beneficial value is well established and efforts to improve its techniques and thereby add to its usefulness are being continuously made. One area of preliminary investigation which has come to the fore in recent years concerns the second above discussed facet of advertising and is based on monitoring the eye movements of a viewer who is watching an advertisement. Analysis of such eye movements supplies valuable information about whether the viewer's attention is sufficiently attracted to those portions of the advertisement which are considered of greatest value in selling the advertised product. Thus, for example, it can be determined whether a photograph showing, say, a brilliant sunrise as background to the product placed in a corner of the picture attracts the viewer's attention to one or the other. If his attention is only briefly drawn to the product and then dwells on the sunrise, it is unlikely that the product has made a memorable impression on him. However, if the sunrise serves to initially attract his attention to the advertisement and his gaze then settles on the product, chances are good that he will remember the product which, in turn, may lead him to purchase it. This is a highly simplified discussion of the analysis done, but it serves to illustrate the valuable contributions of this technique. The same benefits can be derived for movie type advertisements projected on a suitable screen. For purposes of this presentation all such advertisements which may be in the form, for example, of movie film or video tape, will be referred to as movie film. The analytical difficulties, however, are multiplied. This is because the viewer is seeing an ever changing image and each scene of the commercial (as this type of advertisement is commonly called) must contribute satisfactorily to the desired effect. Thus, many scenes must be analyzed, instead of just one as is the case with the photograph advertisement, so that any defects found in a particular scene or in how it coordinates with the rest of the commercial can be corrected. Synchronization for properly recording the view's reactions and what he sees is an essential ingredient not necessary, of course, with the photograph advertisement. Also, greater skill is required to interpret the results of the eye monitoring because of the variables involved.
This eye monitoring technique for preliminary advertisement effectiveness investigation has been in use for some time. Typically, the subject viewer is shown the advertisement and his visual reactions are recorded for subsequent detailed analysis. Should this analysis reveal certain deficiencies, appropriate corrections can be made. In the above-presented example, the correction might be to increase the picture-size of the product or to move it from the corner to the center in order to increase its attraction to an impression on the viewer.
A known apparatus for obtaining the necessary data for this technique is depicted in FIG. 1. The viewer, represented by eye 1, sees an image shown on screen 3 by a rear projector 5. The viewer's head is secured in an apparatus (not shown) so that he can scan the entire screen only by moving his eyes. Projector 5 can be a slide projector or movie projector depending on the type of advertisement and screen 3 can be a projection screen or the screen of a television (TV) set in which case a TV camera (not shown) transmits to the TV set the image picked up from the projector. The remainder of the apparatus serves to sense and record the viewer's eye movements in relation to what he is seeing. More specifically, light source 7 reflects a thin beam of light, 9, off the cornea of the eye. Reflected beam 9' enters light-collection tube 11 of an assembly 12. The beam exiting tube 11 is the size of a dot. Tube 11 includes the optics required to focus the beam properly and maximize its brightness. A filter 13 is preferably placed on light source 7 to produce a red beam because this color is least annoying to the viewer.
Light beam 9' exiting tube 11 encounters semi-transparent silver surface 15 secured between prisms 16 and 18. This mirror-like surface is designed to transmit part of the beam while reflecting the other part. The reflected part of beam 9' passes through a suitable optic 17 and into a TV camera 19. The video signal is recorded on video tape by recorder (VTR) 21 and may simultaneously be displayed on TV set 23 for immediate monitoring. As the viewer's eye scans the projected image, the beam 9 is correspondingly deflected by the cornea so that TV camera 19 can pick up a dot representative of the precise eye location.
The above arrangement suffices to monitor eye movements when the viewer is shown a photograph. For later analysis, all that needs to be done is to superimpose the photograph in a well known manner on the recorded eye movements. Using a slide projector and the VTR on the same screen, for example, is one way to do this. However, when a movie film advertisement is used, it is also essential to know what scene is being viewed as the eye moves to a particular point on the screen. Consequently, the depicted apparatus includes means for simultaneously recording the eye movement and the viewed scene. More specifically, semi-transparent mirror 27 is interposed between screen 3 and viewer 1. It transmits a portion of the light from screen 3, as represented by beams 29 and 31, to viewer 1 and reflects part of beams 29 and 31 to a standard mirror 33. Mirror 33, in turn, reflects this light toward semi-transparent mirror 15. Mirror surface 15 transmits part of this light to camera 19 which now picks up the reflected portion of beam 9' superimposed on the screen image from mirrors 27, 33 and 15.
Needless to say, all the mirrors must be carefully set to critical positions for the apparatus to function properly. The apparatus is calibrated as the operator 25 peers through optic 35 at the transmitted part of beam 9' and the reflected part of beams 29 and 33 from mirror surface 15. The operator sees exactly what camera 19 sees. Beam 9' should be centered when the viewer is looking at the center of screen 3. If not, appropriate adjustment of the relative position of the mirrors is made, such as by movement of assembly 12, which may be placed on a track (not shown) for this purpose.
Inherent to the above-described apparatus are several salient disadvantages. Some of these render the task of the analyst more difficult due to the dim and blurred image the apparatus provides. The dimness of the projected image is attributable primarily to the light-splitting occurring in mirrors 27 and 15. Even a relatively bright projected image appears dim to camera 19. Image sharpness is adversely affected by the different reflective planes present in a semi-transparent mirror which may result in ghost images much like those found on a television set placed in a poor reception area. Image contrast is reduced by the mixing of two light sources in housing 18. This superimposition also reduces the dot brightness. To compensate for the latter, the intensity of light source 7 must be increased but at the cost of possible discomfort to the viewer. In addition to all of the above, if a large screen 3 were to be used, its periphery would not be viewable through mirror 27 and, therefore, this portion of screen 3 will not be picked up by camera 19. Consequently, the analyst cannot know what the viewer is looking at when the area is involved.
Besides complicating the analyst's task, this apparatus is not satisfactory from the viewer's standpoint either. Since the brightness of the projected image is dimmed by mirror 27, the viewer may have to strain in order to see some parts of the advertisement, particularly those in which the light level for certain scenes is somewhat lower. Also, since the size of mirror 27 is fixed for a particular screen size, should a larger screen size be desirable, the screen periphery would be outside the viewing area of mirror 27, as mentioned above. The support frame (not shown) for mirror 27 would thus block part of the screen. Moreover, mirror 33 would also block part of screen 3 should such a larger screen size be desirable. Furthermore, since critical mirror alignment is necessary, the viewer's eyes must be within certain confines due to the limited range of adjustment of such a system. Thus, a tall person must keep his head in basically the same position as a shorter person thereby causing physical discomfort, particularly should the interview be a lengthy one. These deficiencies of the apparatus singly or in combination may comprise an annoyance factor to the viewer sufficient to significantly distort his reactions due to either his inability to see possibly important parts of the advertisement or to the distractions such blockages may cause.
Though at first glance it may appear that the above-discussed problem could be easily overcome by simply moving mirror 27 and/or mirror 33, practicality dictates otherwise. The mirrors must be aligned within certain critical tolerances. To maintain this alignment, the mirrors are mounted on a support base (not shown) which is rather heavy and bulky because it needs to be strong and solid. Were it designed for adaptibility to various screen sizes, its size and weight would be even greater. Since portability, cost, and ease of operation of the apparatus are important considerations should it have to be taken to the viewer rather than vice versa, such provisions are unsatisfactory. In fact, even the support base used in the above discussed apparatus with limited versatility unacceptably reduces the portability of the equipment.
The problems which the apparatus presents to the viewer are a primary cause for its limited usefullness in other respects as well. Thus, because a mirror 27 obscures some parts of a screen larger than the one shown in FIG. 1, the flexibility of the apparatus to show various advertisements with equal effectiveness is sharply curtailed. For example, to ease eye strain it is desirable to test a printed advertisement on a larger screen to facilitate reading. Also, resolution of the eye movements may be enhanced by a larger screen size. This can be important for any advertisement, of which the printed kind is an example, in which fine detail is involved. Furthermore, due to the eye curvature of some people, the dot position of the reflected beam 9' when the viewer is looking at a corner of screen 3 registers off the screen when the dot is superimposed on the screen in housing 18. This overshoot causes analytical uncertainties since it is impossible to determine with precision what the viewer is looking at in such a situation, and no adequate adjustment is available in the apparatus.